Concrete-tamper.



C. L. MOKESSON.

CONCRETE TAMPER.

APPLICATION FILED APR. 5. 191s.

Patented May 12, 1914.

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DDUUUDQDU DUDUDEEUU mmmmmm mm mmmmmmm mmmm um mmmm UD mmmmmm mm mmmmmm mm UDDDEEHDU /QK Tl@ [NVM/TOR CLA'DE L. Mc-KESSON, OF LOS ANGELES, CALIFORNIA.

CONCRETE-TAMPEB.

Specieation'of Letters Patent.

Patented May 12, 1914i.

Application inea aprn 5, 191e. serial No. 759,080.

The object of the invention is to provide a suction tamper which will drive down t-he rock and gravel near the surface and which will bring to the surface a layer of mortar sutliciently thick to be finished with a trowel or float if desired.

The means by which these and other beneficial results are attainedis illustrated in the accompanying drawingsin which:

Figure 1 is a side view of one type of my tamper as it appears ready for use. Fig. 2 is a bottom plan view of the same tamper.

Fig. 3 is a transverse section taken on the dotted line al-a in Fig. 2. Fig. 4 is a bottom plan view of a somewhat different type of tamper embodying' my improvements. Fig. 5 is a transverse section taken on the dotted line b-b in Fig. 4 and Fig. 6 is la cross-sectional view taken at o-c in Fig. 5.

Throughout the several views like characters. indicate like parts and referringto the details of construction 8 is a plate having numerous apertures 9 exte ding from its under to its upper surface. li`or convenience in casting these apertures are usually t-apered toward the top. A 'handle socket 10 is integrally formed on the top of the plate. This socket may be round as shown in Fig.

9. or rectangular as Shown in Fig. 6.

12 is a lexible cover corresponding in size and shape to the top of the plate 8 and is provided witlra centrally located aperture corresponding to the size and shape of a cross section of the handle socket. This cover 12 mav be constructed of cloth, carpet. rubber or similar material. cially adapted tothe use and ispreferred. In the type of my device shown in Figs. 1, '2 and 3 the tlexible covering is loosely secured to the top of the plate 8 by means of screws 17. Wires, rivets or other simple expedients may be used to accomplish the same result.

11 is an ordinary tamper handle.

Rubber is espe In the modified form of my device shown in Figs. 4,' 5 and 6, the fiexible cover is wei glited down by means of a sheet of metal 13 resting uponit. In this form of construction the flexible cover and the metal weight 13 are prevented from turning by being fitted around the angular soeketrlO provided for the handle. The fit around the handle` socket is suiiicicntly loose to allow the flexible cover and the weight to move freely up and down. In some work Where it is desirable that the tamper shall have the maximum amount of suction power it is t'ound desirable to provide rims around each aperture. These rims are designated in the drawings as 14 and a similar rim 15 surrounds the plate 8. 'Ihesc thin rims mayy be driven deeper into the concrete than the tace of the tamper would otherwise penetrate and allow the tamper to be raised higher before air can enter under the tamper and release thc partial vacuum produced by the raising of the tamper.

lVben concrete is intended to receive a finished or dense wearing surface it is usually mixed and moistened until the sand and cement `filling the spaces between the coarscr particles is in u liquid or semi-liquid state and the best results are attained where this condition exists. After concrete, so mixed, is spread und its surface shaped into the desired form it is ready for tamping with my tamper. When thc tamper is dropped on the concrete the rock and course aggregate is driven down and the mortar displaced thereby rises partially filling the apertures inthe plate. The portion of tbeair in the apertures displaced by the mortar escapes under the flexible cover. At the end of the downward stroke the flexible cover falls, valve like, as a result of gravity and momentum, and closes the tops of the apertures. As the tamper is raised air is prevented from entering the tops of tbe apertures by the flexible cover and atmospheric pressure prevents the mortar Jfrom escaping until air entering under the tamper relieves the partial vacuum so created. The mortar within the apertures at the beginning of the upward movement ot' the tamper is raised an appreciable distance before the vacuum is thus relieved and capillary attraction between the mortar raised and the mortar in the concrete lit'ts more mortar to the surface of the concrete. Several vshort quick strokes with this tamper will provide all the mortar ordinarily required for troweling or floating. The action ofthe tamper in drawing the mortar up out of the concrete resembles the action of a lift'pump having a suction inlet. The raising of the tamper liftsmortar in the apertures and draws up more.

At the next stro-ke the mortar is thicker on the surface and rises higher in the apertures. Vit-h several strokes the mortar may be brought up unt-il the apertures are filled and the mortar is forced'out under the flexible cover. The rims around the apertures delay the entrance of air under the tamper until it is withdrawn farther than otherwise and by thus lengthening the` stroke increases the pumping capacity of the tamper.

Variations may be I'nade inthe construction of the tamper and by substituting some of the ordinary forms of valves for the flexible cover but the construction shown is preferred. Broadly the idea of a tamper having y mechanically created vacuum and the method of bringing mortar to the surface of concrete by the use of such a tamper, which may reasonably be termed a suction tamper, is thoughtv to be nevi7 and novel and Having thus disclosed my invention what I claim asnevv and desire to secure by Letters Patent is.

1. A concrete tamper having apertures for the reception and retention of mortar on theA surface of t-he concrete being tamped and means for closing the tops of said apertures when the tamper is liftedl thereby producing suction adapted4 to bring more mortar to the surface of the concrete.

y 2. A concrete tamper consistingof a handle; a plate attached to said handle; apertures in said plate and means for closing said apertures, all substantially as described.

3. A concrete tamper consisting of a handle; a plate attachedy to said handle; apertures in said plate and a flexible cover adapted to close said apertures, substantially as described. v

4. In a concrete tamper, t-he combination of a handle; a plate attached to said handle; apertures in said plate; a flexible cover on said plate adapted to close the tops of said..

apertures at the end .of the downward stroke and means for keeping the said flexible cover 1n operative position, all substantial-ly as described.

5. In Aa concrete tamper, the combination of a handle; a plate attached to said handle; apertures in said plate; rims around the bottom edges of said apertures, and a flexible cover adapted to close said apertures at the end ota downward stroke, all substantially` as described. f

Signed in the presence Witnesses.

CLAUDE L. MOKESSON. 4 In the presence "of- YlB?. MITCHELL, E. P. MoKEssoN.

of two subscribing 

